DEVICE and LINK statements relationship to VTAM configuration

z/OS® Communications Server provides a set of High Performance Data Transfer (HPDT) services that includes MultiPath Channel (MPC), a high-speed channel interface designed for network protocol use (for example, APPN or TCP/IP). Multiple protocols can either share or have exclusive use of a set of channel paths to an attached platform. The term MPC+ is used to distinguish this multi-protocol version of MPC from earlier versions that were restricted to APPN usage only.

MPC provides the user with the ability to have multiple device paths defined as a single logical connection. The term MPC group is used to define a single MPC connection that can contain multiple read and write paths. The number of read and write paths do not have to be equal, but there must be at least one read and write path defined within each MPC group.

MPC groups are defined using the Transport Resource List (TRL), where each defined MPC group becomes an entry (that is, a TRLE) in the TRL table. The user defines the channel paths that are a part of the group in the TRLE. Each TRLE is identified by a resource_name. For details about defining a TRLE, see the z/OS Communications Server: SNA Resource Definition Reference.